Circumferential ridge for a centrifugal fan

ABSTRACT

An air impeller or circumferential fan includes one or more fan blades disposed between first and second plates. The first plate is tapered with respect to the second plate and includes an orifice that allows air to flow through the first plate and past the fan blades. The first plate also includes a circumferential ridge located away from the orifice which provides for more consistent construction of the first plate and, therefore, cheaper manufacturing of the air impeller.

FIELD OF THE INVENTION

[0001] The present invention relates to vacuum cleaners and, more particularly, to an air impeller or centrifugal fan for a vacuum cleaner.

BACKGROUND OF THE INVENTION

[0002] Known tank-type vacuum cleaners are capable of suctioning or receiving dry materials such as debris or dirt and may also be used for suctioning liquids. Additionally, many vacuum cleaners have the capability of being used as a blower to blow debris away using a flexible or rigid hose attached to a blower port of the vacuum cleaner. These tank-type vacuum cleaners typically include a motor having one or more air impellers or centrifugal fans, the rotation of which creates low pressure in the tank to draw material into the tank or creates high pressure in the machine to blow material away.

[0003] Air impellers used in vacuum cleaners usually include two plates with at least one fan blade, and usually a number of fan blades, disposed between the two plates. The fan blades generally extend in a radial direction (and usually in a slightly spiral path) away from the center of the plates towards the outer edges of the plates. Additionally, a hole is disposed in the center of one of the plates to allow air flow created by the rotation of the air impeller to flow through the hole in a generally radial direction between the fan blades and then out through the edges of the plates. In some instances, the hole is surrounded or formed by an axial ridge disposed in the plate. Furthermore, in some cases, the plates of the air impellers are tapered toward each other.

[0004] During the manufacturing process, the plates of known air impellers are typically created using a stamping process. However, the stamping process causes some inconsistencies in the plates, including warping of the plates, incorrect or inconsistent thickness of the plates, and incorrect sizes of the plates. Additionally, chemistry and temper of the material used to create the plates can cause the shape of the plates to vary greatly. This is especially true when one of the plates is created having a tapered or conical contour. However, consistent production of the plates is beneficial to the efficient manufacture of the air impellers. For example, consistent production of the plates could provide such benefits as faster and easier production of the air impellers and more efficient conversion of raw materials as these materials would not be wasted on incorrectly produced plates.

SUMMARY OF THE INVENTION

[0005] In accordance with one aspect of the invention, an air impeller has first and second plates, an orifice disposed in the first plate to allow air to flow through the first plate, one or more fan blades disposed between the first and second plates, and a circumferential ridge located on the first plate at a position away from the orifice. Preferably, the circumferential ridge is located along an outer rim of the first plate and is formed of the same material as the first plate.

[0006] In accordance with another aspect of the invention, a vacuum cleaner includes a housing, a motor and an air impeller with a circumferential ridge disposed within the housing. The vacuum cleaner further includes a shaft extending between the motor and the air impeller, as well as a collection tank adapted to be connected to the housing.

[0007] In accordance with yet another aspect of the invention, a method of manufacturing an air impeller for a vacuum cleaner includes the steps of forming a first plate with a circumferential ridge and an orifice adapted to allow air to flow through the first plate, forming a second plate, and attaching at least one fan blade between the first and the second plates. The step of forming the first plate may include the step of forming the circumferential ridge on an outside rim of the first plate.

[0008] Generally speaking, the formation of the circumferential ridge on the plate reduces the inconsistencies in the plate forming process and enables the manufacture of consistently sized and shaped plates.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a side view of a vacuum cleaner having a blower attachment which enables the vacuum cleaner to operate as a blower;

[0010]FIG. 2 is a cross-sectional view of the vacuum cleaner of FIG. 1 illustrating an air impeller of the present invention;

[0011]FIG. 3 is a perspective view of an embodiment of an air impeller having a circumferential ridge;

[0012]FIG. 4 is a cross-sectional view of the air impeller of FIG. 3;

[0013]FIG. 5 is a perspective cross-sectional view of the air impeller of FIG. 3 and;

[0014]FIG. 6 is a top view of the air impeller of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Referring initially to FIGS. 1 and 2, a vacuum cleaner 30 includes a tank 32 and an upper vacuum assembly 34. The tank 32 is supported by casters 36 and includes a pair of handles 38 which may be used to assist the user in lifting and moving the vacuum cleaner 30. The tank 32 supports the upper vacuum assembly 34. The upper vacuum assembly 34 includes a motor housing 46 having a cover 48. The cover 48 further includes a blower opening 49. The upper vacuum assembly 34 may be of conventional construction.

[0016] A motor 66 is disposed within the motor housing 46 and is connected to or includes a shaft 68 which, in turn, is connected to an air impeller or centrifugal fan 70. When a source of electrical power is applied to the motor 66, the motor 66 rotates the shaft 68 which rotates the air impeller 70. As the air impeller 70 is rotated, air pressure is created in the tank 32. This air pressure can be used to suck debris into the tank 32 via an inlet 71 or can be used to blow debris away by connecting a hose (not shown) to the blower opening 49.

[0017] The motor housing 46 includes a pair of blower air discharge slots 72 disposed such that air drawn into the vacuum cleaner 30 through the inlet 71 is expelled through the blower air discharge slots 72 after being filtered by a filter 74 within the tank 32 when the vacuum cleaner 30 is in the vacuum mode. Alternatively, when the vacuum cleaner 30 is in blower mode, the air is discharged through the blower opening 49. Of course the air impeller 70 and motor 66 are disposed in a conventional manner within the housing 46 to provide proper or desired air flow.

[0018] Referring now to FIGS. 3-6, the air impeller 70 includes a first plate 76, a second plate 78 and one or more fan blades 80 disposed in a slightly spiral pattern between the plates 76 and 78. The first plate 76 includes an orifice 81 bounded by an axial ridge 82 and further includes a circumferential ridge 84 disposed, for example, at an outer rim of the first plate 76. Preferably, the circumferential ridge 84 is formed of the same material as the first plate 76 and is formed in the first plate 76 using the same stamping process used to form the first plate 76. The orifice 81 is disposed on the first plate 76 to allow air to flow through the air impeller 70. When rotated, air flows through the orifice 81 into the areas bounded by the plates 76 and 78 and the fan blades 80 and is expelled from the outer edges of the air impeller 70 by the fan blades 80.

[0019] As best illustrated in FIGS. 4 and 5, the first plate 76 may be radially tapered toward the second plate 78 so that the plates 76 and 78 are closer together at the outer edges thereof than at the middle portions thereof. To accomplish this feature, the first plate 76 may be formed having a tapered or conical contour. Also, as illustrated in FIG. 5, the fan blades 80 may be attached to the plates 76 and 78 using tabs extending through holes in the plates 76 and 78. Of course, any other manner of attaching the fan blades 80 to the plates 76 and 78, such as welding, glueing, etc., may be used instead. FIGS. 5 and 6 illustrate a shaft mounting hole 90 disposed within the second plate 78 to enable the attachment of the motor 66 (FIG. 2) to the air impeller 70.

[0020] During construction of the air impeller 70, the circumferential ridge 84 is formed on, for example, the outside rim of the first plate 76 or at any other location away from the orifice 81. Additionally, the first plate 76 and the circumferential ridge 84 are preferably formed from the same material. The first plate 76 is also formed with the axial ridge 82 which, in turn, creates the orifice 81. The first plate 76 may be formed using a stamping process which stamps the first plate 76 having the ridges 81 and 84. However, the first plate 76 may be molded or formed using any other conventional technique to include the circumferential ridge 84. The second plate 78 is formed in any conventional manner, such as by stamping, molding, etc. to include the shaft mounting hole 90 which allows for the attachment of the motor 66 to the air impeller 70. Alternatively, the mounting hole 90 may be drilled, stamped or cut into the second plate 78 after the second plate 78 has been formed. Thereafter, the fan blades 80 are attached between the first plate 76 and the second plate 78. The air impeller 70 is typically constructed of a thin metal such as aluminum or of any plastic or other suitable material known in the art. Of course, the air impeller 70 may be constructed of a various number of other materials, including various types of metals. If desired, the second plate 78 may also or alternatively be formed to include a circumferential ridge and may be formed to have a tapered contour.

[0021] It has been found that the construction of the first plate 76 including a circumferential ridge such as the ridge 84 at the outer edge of the first plate 76 provides more consistent manufacture of the first plate 76, especially when the first plate 76 is formed to include a tapered contour as illustrated in FIGS. 4 and 5. This consistent manufacture leads to less waste in the manufacturing process, which reduces the overall cost of manufacturing the vacuum cleaner 30. Furthermore, it has been found that the use of the tapered plates on the air impeller 70 provides for a high efficiency blower.

[0022] During operation of the vacuum cleaner, the air impeller 70 is rotated by the shaft 68 connected to the motor 66. When the air impeller 70 is rotated, low pressure is created in the tank 32 which allows debris and other materials to be sucked into the tank 32 through the inlet 71. Alternatively, high pressure created by rotation of the air impeller 70 at the blower opening 49 may enable the vacuum cleaner 30 to function as blower. Highly pressurized air provided by rotation of the air impeller 70 can be concentrated and directed toward debris in order to move the debris from its present location. Of course the air impeller 70 can be used in other types of vacuum cleaners and blowers if so desired and is not limited for use to those illustrated herein.

[0023] Although the present invention has been described with reference to preferred embodiments, one skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. 

What is claimed is:
 1. An air impeller comprising: first and second plates; an orifice disposed in the first plate adapted to allow air to flow through the first plate; one or more fan blades disposed between the first and second plates; and a circumferential ridge located on the first plate, wherein the circumferential ridge is located away from the orifice.
 2. The air impeller of claim 1, wherein the circumferential ridge is located along an outer rim of the first plate.
 3. The air impeller of claim 1, wherein the circumferential ridge is formed of the same material as the first plate.
 4. The air impeller of claim 1, wherein the first plate is radially tapered toward the second plate.
 5. The air impeller of claim 1, further comprising a shaft mounting hole disposed in one of the first and second plates.
 6. The air impeller of claim 5, wherein the shaft mounting hole is disposed in the second plate.
 7. The air impeller of claim 1, wherein the first plate includes an axial ridge forming the orifice.
 8. A vacuum cleaner comprising: a housing; a motor disposed in the housing; an air impeller having a circumferential ridge and an orifice, wherein the circumferential ridge is located away from the orifice; a shaft extending between the motor and the air impeller; and a collection tank adapted to be connected to the housing.
 9. The vacuum cleaner of claim 8, wherein the air impeller further includes first and second plates.
 10. The vacuum cleaner of claim 9, wherein the circumferential ridge is located along an outer rim of the first plate.
 11. The vacuum cleaner of claim 9, wherein the circumferential ridge is formed of the same material as the first plate.
 12. The vacuum cleaner of claim 9, wherein the first plate is radially tapered toward the second plate.
 13. The vacuum cleaner of claim 9, further comprising a shaft mounting hole disposed in one of the first and second plates.
 14. The vacuum cleaner of claim 13, wherein the shaft mounting hole is disposed in the second plate.
 15. The vacuum cleaner of claim 9, wherein the first plate includes an orifice adapted to allow air to flow through the first plate.
 16. The vacuum cleaner of claim 15, wherein the first plate includes an axial ridge forming the orifice.
 17. The vacuum cleaner of claim 8, further comprising a hose connector adapted to direct air.
 18. A method of manufacturing an air impeller for a vacuum cleaner comprising the steps of: forming a first plate having a circumferential ridge and having an orifice adapted to allow air to flow through the first plate, wherein the circumferential ridge is located away from the orifice; forming a second plate; and attaching at least one fan blade between the first and the second plates.
 19. The method of manufacturing an air impeller of claim 18, wherein the step of forming the first plate further includes the step of forming the circumferential ridge on an outside rim of the first plate.
 20. The method of manufacturing an air impeller of claim 18, wherein the step of forming the first plate further includes the step of forming the circumferential ridge of the same material as the first plate.
 21. The method of manufacturing an air impeller of claim 18, wherein the step of attaching at least one fan blade further includes the step of attaching at least one fan blade between the first and second plates so that the first plate is radially tapered toward the second plate.
 22. The method of manufacturing an air impeller of claim 18, further comprising the step of forming a shaft mounting hole in one of the first and second plates.
 23. The method of manufacturing an air impeller of claim 22, wherein the step of forming a shafting mounting hole further includes the step of forming the shaft mounting hole in the second plate.
 24. The method of manufacturing an air impeller of claim 18, wherein the step of forming the first plate further includes the step of forming an axial ridge in the first plate. 